While most people first heard about mRNA vaccines during the COVID pandemic, the science behind them has been something that researchers have been working on for years before the pandemic. The pandemic allowed those researchers to rapidly conduct trials and get the COVID-19 vaccine produced faster than would normally be possible, but there is no doubt that this type of vaccine was on its way regardless.

Today, pharmaceutical companies are working on developing mRNA vaccines for other health problems, including the flu, and some of them are now being used in human trials to determine their safety and effectiveness.

Many people, especially in the healthcare industry, are excited about the potential of mRNA vaccines because they work in an entirely different way than traditional vaccines. Specifically, mRNA uses molecules of nucleic acid called messenger RNA. These molecules got their name because they bring ‘messages’ or instructions to your cells.

Those messages tell the body what to do, including things like making essential proteins that you need. An mRNA vaccine introduces these messenger molecules that have been specifically made to ‘teach’ the cells of your body how to combat a specific virus. The Covid vaccine, for example, encodes the Covid-19 spike protein so that when you are exposed to the real virus, your body can quickly destroy it.

The same method can be used to combat most any virus, and potentially other diseases in the future. The mRNA itself (whether produced naturally or introduced as part of a vaccine) doesn’t last very long in the body, and it cannot enter the cells to change actual DNA. Instead, it ‘teaches’ the cells what needs to be done and is then filtered out of the body as waste.

Cells that have learned how to combat the virus will then maintain that ability for some time. If they are exposed to the virus naturally, they can fight it off and then ‘remember’ how to fight it off for a longer period of time.

With that in mind, it is easy to see how mRNA could be a very effective method for preventing a wide range of viral infections.

The results of the clinical trial on Pfizer’s new mRNA flu vaccines were published in the New England Journal of Medicine, and they are quite positive. Associate Professor Vinod Balasubramaniam is a molecular virologist from Monash University in Malaysia, commented in the study, saying:

“In a large, global Phase 3 trial involving over 18,000 healthy adults (aged 18-64), the mRNA vaccine demonstrated a 34.5 percent higher relative efficacy at preventing lab-confirmed flu compared to a licensed inactivated vaccine (Fluzone).”

The benefit was primarily on the Influenza A virus, which was able to be studied more closely because it is much more common this year than Influenza B.

In the 2022-2023 flu season, the authors of the study say that the standard flu shot had an effectiveness of between 44 and 54% for those under 64 years old. Based on the trial results, the new mRNA vaccine would have been 60-67% effective. This could mean millions fewer flu cases, which could save many thousands of lives each year.

The side effects associated with the mRNA vaccine are not unlike those found in the traditional vaccine, including soreness and mild symptoms. Like the flu shot, the mRNA vaccine would contain no live virus, so it would be impossible to catch the actual flu from the vaccine.

This is major progress in vaccine science and will likely be widely available in the coming years.

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